Antibodies can serve as recognition elements for detection of specific targets for use in medical diagnostics and sensors of various types. The capability of such tests and devices depends on the specificity and affinity of the antibody which is responsible for the core function of the assay.
A monoclonal antibody of the IgG class includes four proteins connected by disulfide bonds (two copies each of the heavy and light chains). The recognition elements that carry out the binding functions of the antibody are located in two specific domains that are part of the heavy and light chain respectively and known as the VH and VL domains. Other aspects relating to antibodies are known to those of ordinary skill in the art and may be found in, e.g., U.S. Pat. No. 8,182,811, incorporated herein by reference.
Single chain antibodies (scFv), which comprise VH and VL domains joined by a linker, can provide an alternative to whole antibodies, in that scFv can be readily expressed in E. coli bacteria rather than requiring more complex mammalian cell culture, and furthermore scFv are readily tailored through genetic manipulation. In contrast, the production of monoclonal antibodies necessitates expensive hybridoma cell culture and careful storage.
Trinitrotoluene (TNT) is a desirable target for sensor development for both terrorism prevention and environmental remediation, since the compound is common component in explosives formulations. Although commercial antibodies exist for detection of TNT, a need exists for antibodies with superior binding characteristics will allow for improvements in TNT detection.